Equipment Part one : The "Container" and the main Parachute.
Written by David Cowman. Written 10th Jan 2005.
Modern skydiving equipment is the culmination of years of experience. Designed to be highly reliable, main parachutes or canopies have evolved from being round " air brakes " to rectangular three dimensional wings which are highly manouverable. Some are more higher performance than others but all have the same key features in common.
The " Container "
While there are several brands of container available again they are designed around the same principles. Each contains a main and reserve parachute. The focus of this article is how your main parachute works and in later articles we will look at particulars of the reserve and emergency systems.
How does the main parachute open ?
The skydiver uses the pilot chute to initiate the opening sequence. The pilot chute is in a pocket located on the bottom of the container . To open , the skydiver pulls the PC out of the pocket and lets go of it.
The pilot chute is grabbed by the passing air and inflates. It pulls out the 2 metre flat rope called the bridle.
As the bridle is coming out of the container, it pulls "closing pin", on the container. This pin holds the main parachute ( inside its " D bag " ) inside the container. Pulling the pin opens the container.
The bridle continues to pull the " D bag "out of the container.
One end of the bridle connects to the pilot chute. At the other end is a bag called the deployment bag, or D-bag. When you pack the parachute, you put it into the D-bag, and then the D-bag goes into the container. The bridle pulls the D-bag out of the container.
All of the parachute's " suspension lines" have been stowed in a zig-zag pattern by looping them through strong elastic bands attached to the D-bag. As the pilot chute and bridle continue to pull on the D-bag, all of the lines stretch out and the parachute having popped out of the bag begins to inflate. The wind inflates the cells of the canopy.
Controlling the speed of opening
What you do not want, however, is for the parachute to open instantantly. If it opens instantantly , you decellerate too quickly. This hurts and can also damage equipment. Therefore, all parachutes have a small square piece of fabric called a slider that holds the lines together and slides down the lines as the parachute inflates. This slows down the opening and helps keeps the lines in their correct groups ( helps prevent tangling ).
Once the Parachute is open the skydiver can use steering toggles to navigate back to the landing area.
Next week we shall look at how the parachute is able to fly.